Plunger clamp

ABSTRACT

An improved toggle operated plunger clamp having control means for inhibiting the movement of the plunger when unloaded. The control means includes adjustable collet and adjustable key means operative to engage the clamp at intermediate positions as well as auxiliary retaining means operative in both the fully closed and fully open positions when the plunger is otherwise unloaded.

United States Patent Sendoykas et al.

[111 3,819,171 [451 June 25,1974

[541 PLUNGER CLAMP [75] Inventors: Jack J. Sendoykas, Grosse PointePark; Alexander W. McPherson, Farmington, both of Mich.

[73] Assignee: Dover Corporation (De-Sta-Co Division), Detroit, Mich.

221 Filed: Mar. 6, 1972 211 App]. No.: 231,997

[521 u.s.c1. .1 ..269/228,269/285 51] rm. (:1 ..B25b1/14,B25b 5/12 [58]Field of Search 269/228, 77, 78, 285, 321 R, 269/321 ME, 201, 256, 59,76, 80, 203, 205-206; 81/363, 367-380, 326

[56] References Cited UNITED STATES PATENTS 1,612,317 12/1926 Reed269/228 X 1,910,121 5/1933 Muntz 279/56 X 2,567,436 9/1951 Lampe 269/228X 2,588,745 3/1952 McKenzie 269/228 X 3,009,694 1 1/1961 Blatt 269/903,027,154 3/1962 Glaubke 269/228 X 3,035,831 5/1962 Blatt 269/201 X Lock269/228 UX 3,628,783 12/1971 Blatt et al. 269/201 3,735,972 5/1973 Blatt269/228 FOREIGN PATENTS OR APPLICATIONS 459,205 l/1937 Great Britain269/256 OTHER PUBLICATIONS Frictional Supports, Kasper, L., ProductEngineering, April, 1945, PP. 272-273.

Primary Examiner-Al Lawrence Smith Assistant Examiner-J. T. ZatargaAttorney, Agent, or Firm-Farley, Forster & Farley [57] ABSTRACT Animproved toggle operated plunger clamp having control means forinhibiting the movement of the plunger when unloaded. The control meansincludes adjustable collet and adjustable key means operative to engagethe clamp at intermediate positions as well as auxiliary retaining meansoperative in both the fully closed and fully open positions when theplunger is otherwise unloaded.

10 Claims, 3 Drawing Figures PAIENTEMuuzsmu 1 WAV w/// PLUNGER CLAMPBACKGROUND OF THE INVENTION Plunger clamps have a clamping memberreciprocably movable back and forth in a clamp body which in turn isusually anchored to a fixture. Such clamps utilize a simple togglelinkage attached to the plunger and the body to reciprocate the plungerand toggle lock the plunger at its extreme extended or retractedposition when in engagement with a workpiece respectively as a pushclamp or a pull clamp. The plungers of such clamps normally haveclearance in the body to allow freedom of reciprocal movement. Thisfrequently leads to undesired gravity actuation of the clampat'intermediate unloaded positions. Furthermore, a loose fit may beunsatisfactory and detrimental to accurate clamping of the workpiece.

SUMMARY OF THE INVENTION The invention comprises an improved toggleoperated plunger clamp including control means to inhibit unloadedmovement of the plunger. The control means include adjustable means toeliminate undesirable looseness of the plunger while allowing forrequired reciprocal action and auxiliary retention means for the fullyextended and retracted positions. The initial positioning accuracy andfirm workpiece positioning of the clamp is greatly enhanced and retainedover relatively long usage by the combination of a split colletadjustment to counteract transverse looseness and a hardened key andflat adjustment to counteract rotational looseness. An adjustable locknut is provided on the plunger to engage a shoulder on the body therebyproviding a stop for toggle locking action in the fully extended plungerposition when a workpiece is not engaged. Conical depressions in thetoggle linkage engageable with conical belleville spring washers provideauxiliary retention for the fully retracted position even in the absenceof workpiece loading.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of the plungerclamp showing portions cut away for clarity;

FIG. 2 is a top elevation of the plunger clamp showing portions cut awayfor clarity; and,

FIG. 3 is a partial end elevation of the plunger clamp.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown, theclamp includes abody substantially cylindrical in shape and welded or otherwise attachedto a base 12. The base 12 includes holes 14 for bolts or other fasteningmeans suitable for attachment to a supporting structure, not shown. Thecylindrical body 10 may be welded to the base 12 in any rotativeposition desired. Concentrically located in the body 10 is a plunger 16having a threaded bore hole 18 suitable for yoke 30 to provide a pivotfor the handle 32. A second pin 38 located in a bore hole 40 throughboth sides of the yoke 30 provides a pivot for one end of the togglelink 42. The other end of the toggle link 42 in turn is attached to theplunger 16 by a pivot pin 44 located in a bore hole 46 through the fork48 of the plunger 16 and the toggle link 42.

The plunger 16 is centered in the body 10 by a collet 50. The collet 50is split at 52 and engages a conical bore hole 54 in the plunger end 25of the body 10. The collet 50 also engages the body 10 in the threadedbore at 56. The inner bore 58 of the collet 50 squeezingly engages theplunger 16. Thus, the collet 50 can be adjusted to take up allclearance, inhibit and eliminate transverseplay of the plunger 16relative to the body 10 and provide desired frictional retention merelyby turning the collet with a wrench in engagement with the hexagonal end60 of the collet.

The plunger 16 includes a flat 62 best shown in FIG. 3, which extendsthe greater part of the length of the plunger and engages a hardened key64 in the shape of a disc, as shown in FIGS. 1 and 2. The disc 64 is setin transverse shoulder bore 66 formed in the wall of the bore hole 68. Aset screw 70 located in a threaded hole 72 in the body 10 adjustablyapplies a force to the key 64 and flat 62 thereby taking up allclearance, inhibiting the rotational of play of the plunger 16 andproviding additional desired frictional retention. Altemately twin setscrews laterally spaced on either side of the vertical plane containingthe plunger axis and engaging the key 64 may be provided.

The bore hole 68 intersects the bore hole 20 to form a shoulder 74. Theshoulder 74 is engageable with a circular nut 76 threaded on the fork 48of the plunger. The nut 76 includes a plurality ofholes 78 adapted forthe insertion ofa metal pin to turn the nut. The nut 76 is suitablyadjusted for engagement with the shoulder 74 for tight toggle lockingaction when the plunger is unloaded, as shown in solid outline in FIG. 1thereby providing auxiliary end position retention for unloaded plunger.When the plunger 16 is loaded by a workpiece, the resistance of theworkpiece provides the necessary force for tight toggle locking actionand the nut 76 is therefore not in forceful engagement with the shoulder74. After proper adjustment of the nut 76, it may be permanentlyretained in position by any of the conventional hardenable glues forsetting a nut in permanent position.

The link 42 includes a downwardly open ended slot 80. The slot 80 isadapted to fit over the central portion of the pin 34 when the clamp isin fully open position, as shown by the phantom outline 82 of the togglelink 42 and handle 32. A conical depression 84 surrounds the closed endof slot 80 on either side and is located in the shallow bore 86 whichsurrounds the slot 80, except for the open end thereof. The conical bore84 on each side of the slot 80 is engageable with the twin opposedbelleville washers 88 mounted on the pivot pin 34. A small collar 90retains the belleville washers 88 separated and against the yoke 30, asshown clearly in FIG. 2. The conical bore 84 and slot 80 are so relatedthat the conical bore 84 is substantially more than in arcuate extentfrom the corner 92 to the corner 94 on either side of the slot 80.Therefore, when the clamp is fully opened and the slot 80 in the link 42pulled down over the shaft 32 and collar 90, the belleville washers 88are resiliently spread by the comers 92 and 94 before snapping intoplace in the conical depressions 84. This produces the snap actionauxiliary retention for the fully open position thus assuring that thehandle and plunger will not move under vibration or otherwise than byintentional operation when the plunger is fully retracted.

We claim:

1. An improved double action toggle plunger clamp comprising a body, aplunger adapted for reciprocal movement within said body, toggleactuating means adapted to reciprocate said plunger and lock same ineither fully extended or fully retracted position when said plunger issubjected to an opposing axial load, and characterized by control meansto inhibit the unloaded movement of said plunger, said control meansincluding adjustable frictional means interengaging between said bodyand plunger at intermediate positions of said plunger, additionalcontrol means for retaining said plunger at one extremity position whensaid plunger is not subjected to an opposing axial load renderedinoperative when said plunger is subjected to an opposing axial load,and further additional control means for retaining said plunger in itsother extremity position where it is not subjected to an opposing axialload.

2. The plunger clamp of claim 1 wherein said control means includesmeans to remove rotational lost motion of said plunger.

3. The plunger clamp of claim 1 wherein said control means includes alongitudinally extending flat on said plunger and an adjustable keymember positioned in said body and adapted to engage said flat to removerotational lost motion of said plunger.

4. The plunger clamp of claim 1 wherein said additional control meansincludes a shoulder in said body and adjustable nut means on saidplunger adapted to engage said shoulder upon reciprocation of saidplunger to one extremity of movement.

5. The plunger clamp of claim 1 wherein said further additional controlmeans includes a conical depression in said actuating means and conicalspring washer means on said body adapted to engage said conicaldepression upon reciprocation of said plunger to one extreme ofmovement.

6. The plunger clamp of claim 1 wherein said adjustable means includescollet means engaging said body and adapted for adjustable tighteningabout said plunger to remove transverse lost motion of said plunger. 7

7. The plunger clamp of claim 6 wherein said control means includes alongitudinally extending flat on said plunger and an adjustable keymember positioned in said body and adapted to engage said flat to removerotational lost motion of said plunger.

8. The plunger clamp of claim 1 wherein said further additional controlmeans includes a slot in said actuating means, a conical depressionextending about one end of said slot and conical spring washer means onsaid body adapted to engage said conical depression upon reciprocationof said plunger to one extremity of movement.

9. The plunger clamp of claim 8 wherein said conical depression extendsmore than about the closed end of said slot.

10. An improved plunger clamp comprising a body, a plunger adapted forreciprocal movement within said body, actuating means adapted toreciprocate said plunger, said actuating means including a handlepivotally mounted on said body and a toggle link pivotally attached tosaid handle at one end and pivotally attached to said plunger at theother end, adjustable collet means concentrically mounted in said bodyabout said plunger, a longitudinally extending flat in said plunger, anadjustable key member positioned in said body and engaging said flat, ashoulder in said body and adjustable nut means on said plunger adaptedto engage said shoulder at one extreme of movement of said plunger, aslot opening in said toggle link having a coni cal depression extendingabout the closed end of the slot, and conical spring washer means onsaid body adapted to engage said conical depression at the other extremeof movement of said plunger.

1. An improved double action toggle plunger clamp comprising a body, aplunger adapted for reciprocal movement within said body, toggleactuating means adapted to reciprocate said plunger and lock same ineither fully extended or fully retracted position when said plunger issubjected to an opposing axial load, and characterized by control meansto inhibit the unloaded movement of said plunger, said control meansincluding adjustable frictional means interengaging between said bodyand plunger at intermediate positions of said plunger, additionalcontrol means for retaining said plunger at one extremity position whensaid plunger is not subjected to an opposing axial load renderedinoperative when said plunger is subjected to an opposing axial load,and further additional control means for retaining said plunger in itsother extremity position where it is not subjected to an opposing axialload.
 2. The plunger clamp of claim 1 wherein said control meansincludes means to remove rotational lost motion of said plunger.
 3. Theplunger clamp of claim 1 wherein said control means includes alongitudinally extending flat on said plunger and an adjustable keymember positioned in said body and adapted to engage said flat to removerotational lost motion of said plunger.
 4. The plunger clamp of claim 1wherein said additional control means includes a shoulder in said bodyand adjustable nut means on said plunger adapted to engage said shoulderupon reciprocation of said plunger to one extremity of movement.
 5. Theplunger clamp of claim 1 wherein said further additional control meansincludes a conical depression in said actuating means and conical springwasher means on said body adapted to engage said conical depression uponreciprocation of said plunger to one extreme of movement.
 6. The plungerclamp of claim 1 wherein said adjustable means includes collet meansengaging said body and adapted for adjustable tightening about saidplunger to remove transverse lost motion of said plunger.
 7. The plungerclamp of claim 6 wherein said control means includes a longitudinallyextending flat on said plunger and an adjustable key member positionedin said body and adapted to engage said flat to remove rotational lostmotion of said plunger.
 8. The plunger clamp of claim 1 wherein saidfurther additional control means includes a slot in said actuatingmeans, a conical depression extending about one end of said slot andconical spring washer means on said body adapted to engage said conicaldepression upon reciprocation of said plunger to one extremity ofmovement.
 9. The plunger clamp of claim 8 wherein said conicaldepression extends more than 180* about the closed end of said slot. 10.An improved plunger clamp comprising a body, a plunger adapted forreciprocal movement within said body, actuating means adapted toreciprocate said plunger, said actuating means including a handlepivotally mounted on said body and a toggle link pivotally attached tosaid handle at one end and pivotally attached to said plunger at theother end, adjustable collet means concentrically mounted in said bodyabout said plunger, a longitudinally extending flat in said plunger, anadjustable key member positioned in said body and engaging said flat, ashoulder in said body and adjustable nut means on said plunger adaptedto engage said shoulder at one extreme of movement of said plunger, aslot opening in said toggle link having a conical depression extendingabout the closed end of the slot, and conical spring washer means onsaid body adapted to engage said conical depression at the other extremeof movement of said plunger.